Electron-discharge device



J. R. WILSON ELECTRON DISCHARGE DEVICE Nov. 17, 1925. 1,562,403`

Filed DeC- 19. 1924 Patented Nov. 17, 1925.

UNITED STATES PATENT OFFICE.

JAMES R. WILSON, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, 0F NEW YORK. N. Y.. A. CORPORATION 0F NEW YORK.

ELEGTRON-DISCHARGE DEVICE.

Application led December 19, 1924. Serial N'o. 756,859.

To all Hmm it may concer-11..'

Be it known that l. JAMES R. Winsox. :i citizen of thc l`nited States of America. rcsiding at New York` in the county of New York and State of New York, have invented certain new and useful Improvements in Electron-Discharge Devices` of which the following is a full, clear, concise, and exact description.

This invention relates to electron discharge devices and has for an object an im proved tensioning support for the cathode of high power vacuum tubes.

This object is attained by providing a resilient member which retains its resiliency at the operating temperatures of high power electron discharge devices, and supporting the cathode therefrom by means of a suspension member of a highly refractory metal capable of withstanding the temperature at which the cathode operates. Monel metal is used' as the resilient member and molybdenum as the suspension member. Since it is not possible to secure a satisfactory weld between these metals directly, it is proposed to arrange a metallic sleeve, having a melting point intermediate that of monel and molybdenum, on one of said members and welding the members to the vmetallic sleeve simultaneously. This art rangement provides an easily7 assembled structure in which the dissimilar metals are joined together at a single point Without affecting the lower melting point resilient spring.

Referring now to the drawings Fig 1 illustrates an electron discharge device employing this invention.

Fig. 2 is an enlarged detailed view of the resilient cathode support and Fig. 3 is an enlarged view in cross section of the welded joint.

The electron discharge device comprises a glass enclosing vessel having an inwardly projecting stem 11. A metallic co1- lar 12 is frictionally held on the stem and carries upright arms 13, of T-shaped crosssection. The u per end of each-arm 13.*is welded to a surffice of a flattened cylindricalanode 14. A pair of rods 15 and 16 are attached to the anode and support insulating members 17 and 18 at the upper and lower ends thereof. A helical control 'electrode or grid 19, having supporting rods 20, is

supported within the anode 14, the rods 2() being inserted in apertures in the insulating members 17 and 1S. A cathode 21 is nrrnnged within the grid 19 and attached to hooks in the member 18. The cathode 21 is held under tension at the upper ends by means of resiliently supported hooks 22. The direct contact between the cathode 21 and the hooks 22 necessitates the use of a highly refractory, high melting point metal. Molybdenum has been found to be satisfactory for this purpose as it is sufficiently ductle so that it may be formed into a hook. A resilient support 23 surrounds the hook 22 and it is formed of a metal which is capable of retaining its high resilient characteristics under high temperature conditions. Monel metal is preferably used for the resilient spring; however, its melting point is lower than molybdenum. The monel resilient support consists of a closely wound Wire helix 24 which fits intoan aperture in the member 17, one end of the wire being bent to form a guide portion 25 extending from one side of the member` toward the member 18, and the other end of the wire being formed into an open helix 26 situated on the other side of the member 17. The free end of the helix 26 is bent so that it bridges the open helix. A thin metallic sleeve 27, of a metal or alloy having a melting point intermediate to that of monel and molybdenum is positioned on the shank end of the hook 22. Preferably, this sleeve is of nickel, since it can be more easily formed and is low in cost. This sleeve may be formed so that there is a sliding lit on the hook or it may be clamped to the shank of the hook. The hook 22 is held within the resilient spring 23 so that the metallic sleeve 27 is ad]acent the bridging end of the helix 26. The point of crossing of the spring and sleeve is then spot-welded, so that the nickel sleeve, hook and spring are fused together. The nickel sleeve affords an easy means ofy compensating for the differences of melting points between the resilient member and suspension member so that it is possible to weld these dissimilar metals without causing the deterioration of the lower melting point resilient spring.

4What is claimed is:

1. In an electron discharge device, a

cathode, a highly refractory su porting wire engaging said cathode,'a he ix composed of a wire resilient at high temperatures, and a metallic sleeve surrounding one of said wires, said sleeve, supporting wire and helix being welded together at a single point.

2. In an electron discharge device, a cathode, a suspension member of high melting point metal engaging said cathode, a resilient member of a lower melting point metal .surrounding said hook, and a metallic sleeve on one of said members, said metal sleeve having a melting point intermediate of that of the other members and being welded to both of said other members.

3. In an electron discharge device, a cathode, a resilient helix of Monel metal, a molybdenum hook passing through said helix and supporting said cathode, and a different metal member surrounding one end of said hook, said member being welded both to said hook and said helix.

4. In an electron discharge device, a cathode, aresilient helix of Monel metal, a molybdenum supporting hook assing through said helix and supporting said cathode, and a nickel sleeve on said hook, said sleeve bein welded to said hook and one end of sai resilient helix simultaneously.

5. In an electron discharge device, a monel wire helical member, a molybdenum suspension member centrally positioned within said helical member, a nlckel sleeve on one of said members, said sleeve being welded to said helical member and said suspension member at a single point, and a cathode supported by said member.

In witness whereof, I hereunto subscribe my naine this 17th day of December A. D., 1924.

JAMES R. WILSON. 

